JPS60178332A - Leakage detecting device - Google Patents

Abstract

PURPOSE:To make the test of gas leakage highly accurate, by covering a material to be examined, whose inside is tightly sealed by a blanking cover, by a chamber, in which helium gas can be sealed from the outside, evacuating the gas from the inside of the chamber, and detecting the gas by a detector. CONSTITUTION:Under the state a material to be examined 1 is tightly sealed by a blanking cover 2, the entire material is covered by a chamber 9. Helium gas 5 is sealed into the material to be examined 1 through the blanking cover 2 and the chamber 9 from the outside and pressure is applied. Thereafter, a vacuum valve 10 is opened and the inside of the chamber 9 is evacuated by a vacuum pump 3. When the inside of the chamber 9 reaches a specified degree of vacuum, the valve 10 is closed and a test valve 11 is opened. The gas 5, which is leaked into the chamber 9, is detected by a detector 6. In this way, the stable detection can be always performed without the effects of the opening condition of a probe nozzle, probing speed and the like.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a highly accurate leak detection device for determining the airtightness of a pressure vessel used, for example, in a gas-insulated switchgear. .

[Technical background of the invention and its problems] Substations and switchyards are constructed around large cities or in coastal areas due to difficulty in acquiring land or for reasons of salt damage prevention. Gas-insulated switchgear is used in which electrical equipment is sealed with an insulating medium such as SF6 gas. This type of gas-insulated switchgear is becoming increasingly high-voltage and large-capacity due to the increasing demand for electricity in urban areas, and is becoming smaller, more reliable, and easier to maintain. is required. Therefore, the airtightness of the pressure vessels used in these gas-insulated switchgears and the like is an important factor that influences the reliability of the insulation performance of the equipment. Therefore,
A method for determining the airtightness of a pressure vessel also requires a high degree of detection accuracy, and a corresponding detection device is required.

A leak detection device using helium gas has been conventionally used as a device for measuring the airtightness of a pressure vessel. The general configuration of this leak detection device will be explained with reference to FIGS. 1 and 2.

First, the apparatus shown in FIG. is sprayed from the outside of the object 1 to be inspected, and the detector 6 detects helium scum leaking into the object 1 to be inspected.

However, pressure is applied to the inside of the object to be inspected, such as a pressure vessel with a gas insulator, but with an inspection device like this, which has a vacuum inside and sprays helium gas from the outside, The disadvantages are that the conditions are different from those in use, and that detection work with high viscosity cannot be performed.

On the other hand, in the apparatus shown in FIG. 2, an object to be inspected 1 is attached to a blind lid 2, and an inlet valve 7 provided in the blind lid 2 is opened to supply helium gas.
Helium gas 5 is pressurized and sealed inside the test object 1, and the helium gas 5 leaking to the outside of the test object 1 is detected by the detector 6 via the probe nozzle 8.

However, in this device, in order to detect -C in the atmosphere from helium gas that has leaked to the outside of the object to be inspected, the detector must detect a minute amount of helium gas mixed with air. Exploration 31! Detection sensitivity is greatly affected by factors such as temperature. In addition, in this case, a high vacuum is required inside the detector due to the principle of detection, and since the suction hole at the tip of the probe nozzle is constantly exposed to atmospheric pressure, a large pressure ratio is generated at the nozzle. You need to endure it. Therefore, the machining accuracy of this part and the operation of the probe nozzle are very difficult, and the opening degree of the probe nozzle does not have a large effect on the operating conditions of the detector, especially the sensitivity, which is a drawback.

``Object of the invention'' 1. The present invention was proposed in order to eliminate the drawbacks of the conventional leak detection device as described above, and its purpose is to improve the sensitivity of leak detection by the pressurization method using helium gas. The object of the present invention is to provide a highly reliable leak detection device.

[Summary of the invention] The leakage detection device of the present invention attaches an object to be inspected to a blind lid,
Helium gas is pressurized and sealed inside the object to be inspected.
After covering the chamber with a vacuum chamber, the inside of the chamber is evacuated and helium gas leaking from the inside of the test object into the chamber is detected. It is designed to detect leakage of the object to be inspected without being affected.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be specifically explained based on FIG. 3. Note that the same members as those of the conventional leakage detection device shown in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, an object to be inspected 1 having a shape capable of being filled with helium gas inside is hermetically sealed by a blind lid 2, and the object to be inspected 1 and the blind lid 2 are entirely covered by a chamber 9. Further, an introduction valve 7 for filling helium gas is connected to the inside of the inspection object 1 through the blind lid 2 and the diagonal cover 9. On the other hand, in Bu'i Shiba-9,
A vacuum pump 3 is connected via a vacuum valve 10. Further, a detector 6 is connected to the diton bar 9 via a test valve 11 in order to detect the degree of leakage of helium gas.

In the leak detection device of this embodiment having such a configuration, first, the object to be inspected 1 is attached to the blind lid 2, and the inlet valve 7 is operated to pressurize and seal helium gas 5 inside the object to be inspected. Then, the whole is covered with a chamber 9. After that, the vacuum valve 10 is opened and the inside of the chamber 9 is evacuated by the vacuum pump 3. After reaching a certain degree of vacuum, the vacuum valve 10 is closed and the dest valve 11 is opened, and the detector 6 detects helium gas leaking from the inside of the test object 1 into the chamber 9 .

In this way, helium gas is pressurized into the test object 1 and the test can be carried out under conditions similar to the conditions in which the pressure vessel of the gas-insulated switchgear is used. Since it is not affected by the atmosphere, leakage gas detection accuracy is significantly higher.

[Effects of the Invention] As described above, according to the present invention, 1. By covering the object to be inspected with a chamber and evacuating the inside of the chamber,
Since the part where the leak is to be detected is in a vacuum state, the sensitivity is no longer influenced by the operating conditions of the detector due to the opening of the probe nozzle, and the influence of the detection sensitivity by the probe nozzle's exploration speed, which is the case with conventional models. This has the effect of making it possible to provide a leakage detection device that can perform stable and highly accurate IC leakage tests.

[Brief explanation of the drawing]

Figure 1 shows an outline of a leak detection device using the conventional vacuum method.
FIG. 2 is a cross-sectional view schematically showing a leak detection device using a conventional pressurization method, and FIG. 3 is a cross-sectional view schematically showing an embodiment of the leak detection device of the present invention. 1...Object to be inspected, 2...M lid, 3...Vacuum pump, 4...Blowing nozzle, 5...Helium gas,
6...Detector, 7...Introduction valve, 8...Probe nozzle, 9...Dimber, 10...Vacuum valve, 11
...Test valve. 7317 Representative Patent Attorney Kensuke Norichika (and 1 other person) Figure 1 Figure 2

Claims (1)

[Claims] It is equipped with a blind lid that seals the inside of the object to be inspected and filled with helium gas, and a chamber that covers the entire object to be inspected and the blind lid. A leak detection device characterized in that the chamber is connected to the chamber, and a vacuum suction device and a helium gas detector are connected to the chamber.